1. Field of the Invention
The present invention relates to a cyan coupler which can be incorporated into photographic light-sensitive materials and produce a dye image having excellent fastness.
2. Description of the Prior Art
Couplers that are used in color photographic light-sensitive materials should form dye images having excellent fastness. N-(2'-Acetamido-.beta.-phenylethyl)-1-hydroxy-2-naphthamide produces a dye image having good fastness by coupling reaction and good spectral absorption properties for cyan color images and is disclosed in U.S. Pat. No. 3,002,836. However, this compound cannot be incorporated into a color photographic light-sensitive material since it does not have the so-called diffusion-resistant group in its molecule. Attempts have been made to introduce a diffusion-resistant group into its molecule, however, when an alkyl group having a large number of carbon atoms is introduced to N-(alkylcarbonylamino-, alkylcarbamyl- or alkylcarbamylamino-substituted phenylalkyl)-1-hydroxy-2-naphthamide type cyan couplers including N-(2'-acetamido-.beta.-phenylethyl)-1-hydroxy-2-naphthamide in order to render them diffusion-resistant, the fastness of dye images formed from these couplers by coupling reaction becomes remarkably worse depending on the position at which the diffusion-resistant group is introduced. In accordance with the present invention, an alkyl group having a large number of carbon atoms is introduced at a position without the accompanying degradation of the fastness of the dye images.